SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '518d5a80f1985663e0db49a665faa501482b780506d2b6889bed16c3b7508427' 
  AND token = 'R15PY97qjTjNgeayLVaDbkhb6LS3vJRNser4UB0t+Ek=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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