SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a011fb17a206b663d986a9507fc62d0547c38e627df7140200af06aefad3b87e' 
  AND token = 'eTBpDG1r36z/iqAqFGPCrL0NSGp9IXq9AfY07FkV6Fo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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