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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dd7f37fc6c8c18780e95e7448eee6b6b8c1051f99000f2e9c9e6c12b4c2e54d4' 
  AND token = 'PaVcxnj31hLzsnbMhrYCyNoWuthULXmVwBrGZUq5obc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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