SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dd204d382389a46bd78b3fca8f0a965fd0fd53044fbfc87959fdce85093a3435' 
  AND token = 'amxkJmD/igDVxeTJwlP+Jp3FR8AAnYBnzGhqO3Nw3t4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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