SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '52c3abac1657ad35acd5c72f3b069cf618b4f899b93c1555accd7585022bc0f3' 
  AND token = 'BHGm1gVmLHjJYXYjO6EtpXKiav6ZMZx5aym9w/EyZGs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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