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SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'af937f39bf2d295d94bfe00ef07be7f43a87c4800dae15c7dd9755f1a6327dcd' 
  AND token = '6ViwBIWzD+dQdb2AToZC6Ag6eA1zYSkYxpb3bzwtIPo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}