SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '50785945cd4ebe69b2e5e001b5c3860e0b23dcc7b0ca82c6ff79dc388f4c05e5' 
  AND token = 'DKd8RdvMLCGKlqn/6MjiGnCZeMU38JYHmNdUL5EObBA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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