SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4313296f3ad9a04869ab1447d0be19e7d5762c67cc27b64641e69227611a1a78' 
  AND token = 'ftJvVJiaev1TngSOEnhWjZX/JAys4AS8RpkuHISUt2g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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