SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'dd9c32af2c996cafe892b72003408a143cf45750107d15e163929012d3b48e52' 
  AND token = 'g/RZcWdQaEFk8V4iVLAWf2oWAw3+qwqtAcmoHHBZ/g4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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