SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f08701c46e24008ee67a99798c94bfc2a1803d2923c44fd0ef94b0128df1beec' 
  AND token = 'JyWEQVkoSyMOY5s/cytWEgJHXNrBuNPGXtNgm7Nf2G0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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