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SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'ab673d6fb4e0d3cbe8e4b09ef3ed77ed62b575414fcddb81601079ee8f4a6b40' 
  AND token = 'JxotHh2UoWQ99HTnIiyaP9hd+glHwM39EQ6CAATOrRc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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