SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7262c6fb73e881da476be67b69692166226e7e30b8fa69b7b8744b2fcd022f29' 
  AND token = 'vPD3CuBnessIak5ELOAwhjWWCknJprHAsYTkRjAhrj0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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