SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a780eabb2d124953756ebbe4a5c2410cfe0f8c4df30db76ce5cf2ddf651bfa73' 
  AND token = 'U+EMXqwXyp7ipRZAGyH0TGdXsgos9IzBXn1tzBf2CLg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00065

JSON explain

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