SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '67eb757184e6aaf1cccbb9603a626f86562121f1b43f0fa26aac42a11796e522' 
  AND token = 'H/mDOJqF4HKwWem12Bla8M5hBEmwG353xUBwkm4j0gg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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