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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c4bb53d3e9aaf16cd056c34e1575e3b37411ccaa420cd1ba19164a44b542a218' 
  AND token = 'ROw+R1Hfd8bMs9Mu5lVP1qBUYWDS69Z1ZYvozQSGrhs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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