SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '92d6f7cd852e1c0493fa97699f34e03b1e29133d433b2a6144e6733c460184a4' 
  AND token = 'E7KfKA6EYYtuGkgDiN/I5RDXUmorY7ezd+BjywFV3Ow=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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