SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '39f2ba0570794fddf0ccf698c91d7d0f1fb66db51b62a503aff13f373013ce2e' 
  AND token = 'Ug52zuGFQ8pGYO2g5ZsD1ksFWhQ0QENkndNHi2YyDsY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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