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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a7ea5e8018e0cab3c82a1efc1d53ed98d80088c898258b2cc15ee6c1a6eb0627' 
  AND token = 'cfXqfL3ul/Clz2ZoUb6y3hwrdTpzywMgsgNRv6arR8Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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