SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '6b37f60f310b691a206bd65536f419f12939a72e81536a98b1ae4b16332ec5bd' 
  AND token = 'Co/cVJiwVSOb2QHm7nw2AKLDX2esUS8qpLMQfisvDL0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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