SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8f789d176713df2844d437b535bdd9cc6fea2b85b7527605716565f8bbfb2fa1' 
  AND token = 'iP1CoIB5jJC8H5Jf2sd7hytny/jrf75xCLQmilq5K+k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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