SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '157e189816dccb8999166326d5dfc28a517a6313f407e36551ed70eca276e49c' 
  AND token = 'jB70pFOuQxWQ6EyIvNPBm5qIhlrDmrvqzB2Af1AtPQU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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