SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'c3f3d1818ded0c353eaf06fbd9e7f6cadc45636816c49775d898a47d9d36abb1' 
  AND token = '2REQEbsMoIFqBmfHvHCzNl7VLBd13i5+/W4FZr1GFKg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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