SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '75e56045e40eef34a0f7b43f960ac0a52a0b4dcba244a7398c5497a92e2447ca' 
  AND token = '1VoNwwSf7ymCiW7PbGuaOJUAc2XPanViOoZQp4LFVo8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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