SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '600cb13c772806a0f3a66c2eb30d6637ef844ae78d4affaadb23b68ececb1c95' 
  AND token = 'iEjehd39Efdgq692e+2OpbGYTY7lf7L68qn+mnwJIvk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00053

JSON explain

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