SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '99e6fafaef0e449f70c14c9aad91af1788936321b526b55957dbe09e974f2825' 
  AND token = 'agm0Fe+/w19FuJvSMetRPiqOB1DXzUZOc4dULiEotJ0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00050

JSON explain

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