SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f56e882e399d1ca194923389339397b2f3396c40c98fc07b7baae75df142ea5b' 
  AND token = '7QFDD8S+wYjauLDkmItwaEiNNkGFIU4hDsOQEwwcQaE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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