SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '256bafcfeb5cb419c5ad85a39892f34dabf4ba2ca81a6e680fe966b43bc28195' 
  AND token = 'J8/CHjNJHeCfXeuFYgwXOsJTUvh4t50ALQ1QBrT65XM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}